Try also to install the patch from Saturday and execute the code, to see how
the tab-local variables are used to communicate between :initcode, and
:activationcode.

I deactivated the :deactivationcode, because it is not useful for me, and I
wanted to keep the code minimal.



Alin



2010/12/7 Alin Soare <as1789@gmail.com>

>
> > The idea is that I added to struct frame a list of tabs.
>>
>> Where is it?  In the frame's parameters?  Or is it accessed via a new
>> frame-tabs and set-frame-tabs?
>>
>> struct frame
> {
> ...
>     /*
>      * an alist  of the form ((alist_tab_parameters))
>      */
>     Lisp_Object tab_bar_items;
> ...
> }
>
>
>
>> In any case, how difficult would it be to generalize your code so the
>> tabs can be attached to a window rather than a frame, or even to an
>> internal window (i.e. internal windows are those that are somewhere
>> along the window tree and hold various actual windows: currently your
>> tabs are at the root internal window).
>>
>>
> I did not think about. Not too difficult.
>
>
>
>>  > A tab is an alist of
>>
>> > (
>> >   (:name "string-name")
>> >   (:init-code (lambda () ... code) )
>> >   (:activate-code (lambda() ... code) )
>> >   (:deactivate-code ... )
>> >   (:environment list-of-symbols)
>> > )
>>
>> What's the init-code for?
>>
>
> The init code is executed only when the tab is created. In my script it is
> used to memorize the current window config into a variable 'sym. The
> variable sym must be tab-local during the tab existence.
>
>
>> I suspect activate is run when you click on the tab and deactivate is
>> run when you click on some other tab.
>> What's environment and how is it used?
>>
>>
> An environment keeps tab-local variables. For example , every tabmust know
> about the window-configuration when it was created , and extract from its
> own environment the value of that win config.
>
> No other tab needs to see its own windows config.
>
>
>> > This is the function that defines a tab. It initialize a symbol sym with
>> the
>> > value of current-window-config. The symbol 'sym is passed to
>> > (make-terminal-frame), that creates the tab.
>>
>> I don't understand this "symbol sym" business.
>>
>>
>
> I have just explained. It is not interned in the main obarray, and it is
> passed to the environment of the tab.
>
>
>
>>  > ;; this is a definition of a tab as a window configuration
>> > (defun make-wc-tab (parms)
>> >   ;; save curent win config
>> >   (setq sym (make-symbol "winconfig"))
>>
>> Here, you're setting a global variable, which is wrong.  It's also very
>> unclear why you want a symbol here.
>>
>
> It is not global. It is not interned, and it becomes tab-local.
>
>
>
>>  >   (set sym  (current-window-configuration))
>> >   ;; make a tab that keeps a window configuration. When it is created,
>> >   ;; it memorizes the current win config. When it is activated, it
>> >   ;; restores the memorized win config
>> >   (make-terminal-frame
>> >    (list '(tab . t)
>> >      '(tab:name . "WinC")
>> >      '(tab:activate
>> >        .
>> >        (lambda ()
>> >          (set-window-configuration
>> >           (eval (cdr (assoc 'tab:env (frame-parameters) ) ) ) ) ) )
>>
>> `eval' is bad.  Stay very far away from it.
>>
>> >      ;; save the current win config into the tab environment
>> >      (cons 'tab:env sym) ) ) )
>>
>> How do "tab:activate" and friends relate to the
>> previous :activate-code thingies?
>>
>
>
> Via tab-local variables.
>
> In this moment I added code to modify the environment of a tab only via the
> initialization of the tab with make-terminal-frame, but I can add a function
> to operate on tab-local variables even after the creation of a tab.
>
> For example, I did not add the tab:init code to tab's alist, because it is
> runned only to creation, in make-tab, before calling make-terminal-frame.
>
> But if I want to be able to re-initialize a tab, then a function to operate
> on tab's environment is required.
>
>
>>
>> I don't understand the above call to `make-terminal-frame': does it
>> create a new frame, or just a new tab?  If the first, then I don't
>> understand how it works, and if the second, it's wrong because adding
>> a tab should have nothing to do with frame creation.
>>
>
> The fact that make-tab calls directly make-terminal-frame is just a legacy
> of the old code, when a tab used to be just a frame.
>
> Imagine that emacs had lexical binding. Then we woud not need a tab
> environment, because that environment would be included insode the
> evaluation process, when the closure that represents the tab is initialized.
> But because emacs is not able of closures, I need a tab environment, to be
> able to communicate between the
>
>
> (:init-code (lambda () ... code) )
> (:activate-code (lambda() ... code) )
> (:deactivate-code ... )
>
> of the same tab,
>
> Note that inside my implementation of make-tab, the variable 'winconfig has
> a different value for every tab. When :activatecode is called ,
>
> > (lambda ()
> >          (set-window-configuration
> >           (eval (cdr (assoc 'tab:env (frame-parameters) )
>
> (cdr (assoc 'tab:env (frame-parameters) )  returns the variable 'winconfig,
> id est sym.
>
>
>
>
>
>
>